Elevator system

ABSTRACT

An elevator system including an elevator car and counterweight interconnected via hoisting roping for movement in the hoistway of a building having a plurality of landings to be served by the elevator car. Compensation for the hoisting roping includes a chain which interconnects the car and counterweight, and a compensator sheave which guides and tensions the chain. The sheave includes a circumferential groove formed by first and second axially spaced elastomeric members, with the grooves being sized such that alternate links of the chain extend edgewise into the groove, while the intervening links rest against the outer peripheries of the first and second members.

United States Patent [191 Tosato et al.

[111 3,810,529 1451 May 14, 1974 ELEVATOR. SYSTEM [75] Inventors:Lawrence Tosato, Millburn;

Frederick Solymos, Glen Ridge, both of NJ.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: May 25, 1973 [2i] Appl. No.: 364,162

[52] US. Cl. 187/94, 254/190 R [51] Int. Cl B66!) l7/l2, 866d H36 [58]Field of Search 187/94; 254/190 R [56] References Cited UNITED STATESPATENTS 3,279,762 l0/l966 Bruns l87/94 X Primary Examiner-Richard E.Aegerter Assistant ExaminerH. S. Lane Attorney, Agent, or Firm--D. R.Lackey 5 7] ABSTRACT An elevator system including an elevator car andcounterweight interconnected via hoisting roping for movement in thehoistway of a building having a plurality of landings to be served bythe elevator car. Compensation for the hoisting roping includes a chainwhich interconnects the car and counterweight, and a compensator sheavewhich guides and tensions the chain. The sheave includes acircumferential groove formed by first and second axially spacedelastomeric members, with the grooves being sized such that alternatelinks of the chain extend edgewise into the groove, while theintervening links rest against the outer peripheries of the first andsecond members.

9 Claims, 9 Drawing Figures PATENTEBm 14 1914 same or 3 FIG ELEVATORSYSTEM BACKGROUND OFTHE INVENTION 1. Field of the Invention Theinvention relates in general to elevator systems, and more specificallyto elevator systems which utilize chain compensation for the hoistingroping.

2. Description of the Prior Art When the total travel distance of anelevator car in a building can exceed about 100 feet, the weight of thehoisting ropes which interconnects the car'and counterweight via thetraction sheave, adds significantly to the unbalanced load which must belifted and accelerated by the elevator drive machine, with the amount ofunbalance continuously changing as the elevator car and counterweightmove in the hatchway. Thus, it is conventional to provide some type ofcompensation 7 system to reduce the unbalanced load for any position ofthe car and counterweight in the hoistway. The compensation system makestorque requirements more uniform and assists in landing accuracy.

Conventional or ordinary link chains are used for the compensatingweight on elevator systems which operate below about 400 feet perminute. Chain compensation is attractive because of its low cost, butchains become excessively noisy above speeds of 400 feet per minute.Thus, a plurality of wire ropes reeved about a weighted compensatorsheave are conventionally used on elevator systems which exceed a speedof about 400 feet per minute.

Since chain compensation has distinct economic advantages over ropecompensation, ways are constantly being sought to reduce chain noise andchain sway, to thus enable chain compensation to be successfully used athigher elevator speeds. Co-pending application Ser.

No. 240,241, filed Mar. 31, 1972, now US. Pat. No. 3,768,596 which isassigned to the same assignee as the present application, teaches anarrangement for reducing chain noise, which arrangement extends theupper speed limit for chain compensated elevator systems to about 500feet per minute. With this arrangement, resilient spacers formed of amaterial such as rubber, are disposed about alternate links of thechain. The spacers are dimensioned to fully extend the links and tomaintain them in their extended position, which reduces the noise in thenatural loop of the chain formed below the car and counterweight, and italso reduces the noise due to the chain striking components in thehoistway due to chain sway, by using spacers which have an out sidediameter larger than the width dimension of the links.

US. Pat. No. 2,537,075 teaches the use ofa substantially U-shaped rubbertire on a sheave for reducing chain noise.

Resilient spacers, while successfully increasing the top speed limit ofa chain compensated elevatorsystem to about 500 feet per minute, reducethe economic advantage of chains over wire ropes, since the resilientspacers are disposed over alternate links of the chain oversubstantially the complete length of the chain. Further, while the noisecreated by the chain striking the sides of the hoistway is reduced, itwould be desirable to completely eliminate chain sway, if it can beaccomplished economically and without creating maintenance problems.

Reeving the chain about a sheave which is faced with sound deadeningmaterial prevents sway of the chain and reduces chain noise in the loop,but at the expense of increasing maintenance costs. The chain links diginto the firmly backed sound deadening material, resulting inaccelerated wear thereof.

SUMMARY OF THE INVENTION Briefly, the present invention is a new andimproved elevator system which includes an elevator car andcounterweight interconnected via hoist roping. and via compensation forthe weight of the hoist roping. The compensation includes a link chainand a sheave. The link chain is connected to the bottoms of the car andcounterweight, extending downwardly therefrom about the sheave, which isdisposed in the pit.

The sheave includes elastomeric means disposed about its periphery. Theelastomeric means may be a single structure having first and secondaxially spaced members which extend outwardly from a common back portionto define a circumferential groove; or, it may include first and secondindependent members which are held in spaced relation to provide acircumferential groove. In a preferred embodiment of the invention, thefirst and second members are substantially cylindrical and tubular incross-sectional configuration.

The first and second members are sized and axially spaced such thatalternate links of the chain extend edgewise into the circumferentialgroove while the intervening links remain outside the groove, the flatbroad sides of which are supported by the outer peripheries of the firstand second members. The depth of the groove is selected such that itexceeds the dimension of the portion of the link which extends into thegroove, precluding any digging of the link into the elastomeric materialor the backing support therefor. The sides of the members which definethe groove support and contact opposite sides of the links which extendtherein, providing a positive guide for the chain. Compression of thefirst and second members by the flatwise sides of the chain linkscompresses the cylindrical members into an elliptical configurationwhich reduces the width of the circumferential groove to provide a firmguide for different chain sizes without the necessity of changing theunstressed width of the circumferential grooves.

BRIEF DESCRIPTION OF THE DRAWINGS l a sheave constructed according tothe teachings of the invention, which may be used for the compensatorsheave shown in FIG. 1;

FIG. 3 is a fragmentary view of one edge of the sheave shown in FIG. 2;

FIGS. 4,5, 6, 7 and 8 are cross-sectional views of a portion of thesheave shown in FIG. 2, taken between the arrows IV-IV, illustratingdifferent structural arrangements which may be used for providing acircumferential groove in the sheave; and

FIG. 9 is a perspective view of an elevator system which may beconstructed according to the teachings of the invention. I

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, andFIG. 1 in particular, there is shown a traction elevator system 10constructed according to the teachings of the invention. Elevator system10 includes an elevator car 12 mounted for movement in a hoistway 14 ofa structure or building having a plurality of floors, indicatedgenerally at 16, which floors are served bythe elevator car 12. Anelevator drive motor 18 may be mounted on the floor of a penthouse inthe building, which floor is illustrated generally by line 20, with thedrive motor having a drive shaft 22 to which a traction sheave 24 issecured. An idler or deflection sheave 26 may be secured to the lowersurface of the penthouse floor 20, if required.

Hoist ropes or cables 28 interconnect the elevator car 12 with acounterweight 30. The hoist ropes 28, as illustrated, interconnect theelevator car 12 and counterweight 26 with a one-to-one ropingarrangement, wherein they are directly connected to the crossheads ofthe elevator car 12 and counterweight 30, but a twoto-one roping may beused for either the car, or counterweight, or both, if desired.

Compensation for the weight of the hoist ropes is provided, according tothe teachings of the invention,

by a chain 32 and a compensator sheave 36 disposed below the travel pathof the car 12, i.e., in the bottom part 38 of the hoi'stway l4, commonlyreferred to as the pit, with the compensator sheave 36 being mounted forrotation about its axis 37. Buffers for the car and counterweight 30 arealso disposed in the pit, but they are not shown as they may beconventional.

Sheave 36 is constructed according to the teachings of the invention toreduce the operating noise of the chain 32, to prevent sway of the chain32 'at all elevator speeds, and to accomplish these silencing andguiding functions without incurring offsetting economic penalties suchas excessive initial cost, increased maintenance, or both. Sheave 36 isalso constructed to achieve theseresults when used with elevator speedsup to about 700 feet per minute, allowing chain compensation to be usedat elevator speeds at which only rope compensation was heretoforeconsidered practical.

FIGS. 2 and 3 are side and end elevational views, respectively, ofsheave 36, which views are shown partially cut away in order to moreclearly illustrate the teachings of the invention.

Except for its outer periphery, sheave 36 may be'of any suitableconventional construction, including a cylindrical outer metallic member40, an inner metallic structure 41 having a opening for receiving ashaft 42 upon which the sheave 36 is rotatably mounted, and means showngenerally at 44, such as a web or plurality of spokes, for supportingmember 40 from the inner structure 41.

Elastomeric means 50 is disposed about the outer peripheiy ofcylindrical member 40, providing a circumferential groove 52 about theouter periphery of the sheave 36.

Elastomeric means 50 includes first and second axially spaced members 54and 56 which are disposed between plate-like metallic guide members 58and 60. Guide members 58 and 60, which may be washer or disc shaped, arefirmly secured to opposite sides of the cylindrical member 40, such asby screws 62, to form a circumferential trough or channel about sheave36.

The construction of the elastomeric means 50 and its dimensionalrelationship with the chain 32 may be more readily apparent by observingcross-sectional views of the elastomeric means and chain, with theelastomeric means 50 constructed according to different embodiments ofthe invention in the different views. I

Specifically, FIG. 4 is a cross-sectional view of elastomeric means 50and chain 32 taken between and in the direction of arrows IV-IV asillustrated in FIG. 2. The first and second members 54 and 56 areindependent in this embodiment, i.e., not connected to one another, eachhaving a circular cross-sectional configuration, and each formed of asolid rod of elastomeric material. The elastomeric material ispreferably polyurethane, because of its excellent wear characteristics,but any suitable elastomer may be used. The members are each formed intoa continuous loop having an inside diameter equal to the outsidediameter of the cylindrical member 40. The outside diameter of thematerial from which members 54 and 56 are formed is selected to providea gap between the members 54 and 56 when these members are placed withinthe channel formed by guide members 58 and 60 and axially spaced suchthat they contact the guide members 58 and 60, respectively.

The chain 32 is an ordinary link chain having a series of interconnectedmetallic links, with alternate links 72 being of like orientation, andthe intervening links 74 being of like orientation. The centerline 76through the opening of link 72 extends in the same direction as andparallel to the centerline 37 of the sheave 36, while the centerline 78of link 74 extends in a direction perpendicular to the direction ofcenterline 37. The alternate links 72 extend edgewise into thecircumferential groove 52 provided by gap 70, while the interveninglinks 74 lie flatwise on the outer peripheries of membe'rs 54 and 56.The edgewise dimension of the links .72, which is the dimension of thestock from which the links are made, is about the same as the dimensionof gap 70, and there may be a slight interference fit between the linkstock and the dimension of gap 70 in order to accommodate differentsizes of chains without modification of the sheave, and still provide apositive guide for the edgewise oriented links 72. As illustrated inFIG. 4, the imaginary lines 80 and 82 of the stock which forms the twosides of link 74, which lines are parallel with the centerline 78 of theopening of link 74, extend through the axes of members 54 and 56, butdifferent sizes of chains may vary this relationship somewhat whilestill resting the sides of the intervening links against the outerperipheries of members 54 and 56. A line 84 disposed through the axes ofmembers 54 and 56, which line is perpendicular to lines 80 and 82,intersects the axis of the side of link 72 which extends into thecircumferential groove 52, but this dimensional relationship may changeslightly with different sizes of chains, and with the compression of theresilient elastomeric material due to the tension of the chain 32produced by the weight of the sheave 36 and by any auxiliary bias meanswhich is used to provide the desired tension in the chain. It isimportant to note that the side of link 72 which extends into thecircumferential groove 52 does not contact the bottom 90 of the groove,that the edgewise links 72 are positively guided by the sides of members54 and 56 which define the grooves, and that the links 74 do notextendinto the groove but are supported flatwise on the outer peripheries ofthe members 54 and 56. These relationships are necessary in order toprovide a sheave which will guide the chain 32 without any tendency ofthe chain to ride up out of the groove and without any digging orscraping contact between the chain and the elastomeric material whichwould excessively wear and severely shorten the useful operating life ofthe sheave. It will also be noted that these relationships may bemaintained for any given sheave dimension for a predetermined range ofchain sizes. In other words, it is not necessary to provide a sheave foreach chain size, as a given sheave will accommodate more thanone chainsize.

As hereinbefore stated, the sides of the flatwise oriented links 74 bearagainst the members 54 and 56 with apredetermined force determined bythe amount of tension the compensation system is designed to introduceinto the chain. This force against members 54 and 56 compresses theresilient elastomeric material from which the members 54 and 56 areformed, to provide a substantially elliptical cross-sectionalconfiguration in the portions of members 54 and 56 which are under thepressure points. The dimension of gap 70 is thus reduced at thesepressure locations to even more firmly grip the sides of the links 72and to perform this gripping function over a predetermined range ofchain sizes. FIG. 5 is a cross-sectional view which is similar to thatof FIG. 4, except the elliptical cross-sectional configuration of theelastomeric members when stressed is promoted by forming the members 54and 56 from tubular material, which enables them to be compressed moreeasily for any given chain force against their outer peripheries. Sincemembers 54 and 56 are modified in FIG. 5, they will be referred to asmembers 54' and 56' when describing this embodiment.

Members 54' and 56' define central openings 92 and 94, respectively,with the wall thickness being selected to provide the desiredcompression of members 54' and 56', and thus the desired dimensionalchange of the circumferential groove 52, as the members 54' and 56' arecompressed or stressed.

FIG. 6 is a view which is similar to that shown in FIG. 5, with FIG. 5representing the relationship of the chain 32 and elastomeric means 50just prior to the chains compression of the elastomeric means, and FIG.6 represents their relationship after members 54' and 56' arecompressed. It will be noted that the central axis 91 of the side ofchain link 72 which extends into the circumferential groove 52 movesdownwardly by a dimension 96. The movement of the axis 91 oflink 72below the axes 93 and 95 of members 54' and 56, respectively, as viewedin FIG. 6, is desirable as it exerts an even greater aligning force onthe links 72. The sides of the members 54' and 56' which define the gapdimension 70 of groove 52 tend to pull the chain links 72 towards thebottom 90 of the groove.

While the members of the elastomeric means 50 which define thecircumferential groove in the sheave 36 may be independent members, theyalso may be part of an integral structure which may be formed such as byextruding the elastomeric material through a die having the desiredconfiguration. Embodiments of the invention in which members 54 and 56are portions of a single unitary structure are illustrated in FIGS. 7and 8. Since elastomeric means 50 is an entirely different structure inFIG. 7, it will be referred to as elastomeric member 100. Elastomericmember 100 includes solid projections 102 and 104 which extend outwardlyin spaced relation from a common side of a back portion 106. Elastomericmember 100 has a smooth inner surface defining a diameter selected tosnugly fit the outside diameter of the cylindrical member 40. Theprojections 102 and 104 preferably have a substantially circularcross-sectional configuration, except of course where they are connectedto the back portion 106, and they function as hereinbefore describedrelative to the embodiment of the invention shown in FIG. 4. The members102 and 104 may function to reduce the gap dimension solely bycompression of the members by the flatwise oriented links 74, in whichevent the bottom of the groove would be disposed in the locationillustrated by the broken line 110, which location is substantiallytangent to the circular configuration of members 102 and 104. Thereduction in the width of the of the circumferential groove 52 may alsobe accomplished by a combination of compression and cantilever bendingof members 102 and 104, if desired, by lowering the bottom of the grooveto the location indicated by reference numeral 112 in FIG. 7.

FIG. 8 illustrates an embodiment of the invention which is similar tothe embodiment shown in FIG. 7, except members 102 and 104 are hollow ortubular. Since member is modified in this embodiment, it is referred toas elastomeric member 100', and its extensions are referred to withreference numerals 102 and 104. As illustrated, projections 102' and 104define central openings 114 and 116, respectively, and they function ashereinbefore described relative to the embodiment of the invention shownin F I65. 5 and 6.

If it is desired to tie or lock down the sheave 36, such that the sheave36 cannot move upwardly beyond a predetermined point, any conventionallockdown arrangement may be used, or the lockdown arrangement disclosedin co-pending application Ser. No. 347,285, filed Apr. 2, 1973, which isassigned to the same ass'ignee as the present application, may be used.A compensation system with a lockdown feature, as is well known in theart, applies a predetermined tension to the compensating rope or chainwhile automatically accommodating permanent and elastic changes in thelength of the hoisting rope. The upward movement of the sheave, however,is limited, in order to tie the car and counterweight together toachieve similar rates of deceleration for both the car and counterweightduring a buffer stop of either, or a safety stop of the car.

FIG. 9 is a perspective view of an elevator system which includestensioning and lockdown apparatus 122 which may utilize the teachings ofthe invention hereinbefore described. In this embodiment, an elevatorcar 124 and counterweight 126 are interconnected by hoist roping 128which is reeved about a traction sheave (not shown), with the tractionsheave being driven by drive means shown generally at 130. Two ordinarylink chains 132 and 134 are used to provide compensation for the hoistroping 128, with the chains being ,connected to points spaced equally onopposite sides of the center gravity of the car, and to similar pointson the counterweight. The spacing 136 between the two chains may be anysuitable dimension. The car and counterweight buffers may be disposedbetween the chains, in which event the dimension 136 would be greaterthan illustrated in H0. 9.

Each chain has the ends of its loop spread by a dimension which is muchgreater than would be provided by a natural loop, to provide good carbalance, without requiring the use of a sheave having the necessarilylarge diameter required to achieve this spread. This resuit is obtainedby using two smaller diameter sheaves for each chain. The distancebetween the axes of these smaller diameter sheaves is made adjustable sothat the desired chain spread may be obtained without changing theconstruction of the sheaves themselves.

Specifically, chain 132 is disposed to run about first and secondsheaves 140 and 142, and chain 134 is disposed to run about first andsecond sheaves 144 and 146, with these sheaves each being constructed ashereinbefore disclosed relative to sheave 36 shown in FIG.

.2. Sheaves 140 and -144 are mounted for rotation on a mension 152between axes 148 and 150 is selected for each application, and isadjustable so field changes may be made, if necessary.

Sheaves 140, 142, 144 and 146 are mounted on a common frame 160, and theframe 160 is pivotable about axis 162 in a vertical plane. Frame 160 maybe constructed of two spaced angles 164 and 166, with a plurality ofopenings 168 disposed in the facing portions of the angles for rotatablymounting the sheaves and for adjusting the dimension 152 between thesheaves. Means for pivoting the frame 160 is provided at one endthereof, such as a hinge for each angle, with ahinge 170 for angle 164being illustrated in the figure. One side of the hinge 170 is connectedto the angle 164, and the other side is fixed to a vertically extendingmounting member, such as angle 172. in like manner, a hinge would beconnected to angle 166, and to a vertical mounting member or angle 174.

The frame 160 is biased downwardly about the pivot axis 162 by anysuitable biasing means, such as compression springs 176 and 178, but asingle spring may be used if desired. Rod members 180 and 182 each haveone end fixed to angles 172 and 174, respectively, and they extendthrough openings in angles 164 and 166, through lower spring seats 184and 186, through springs 176 and 178, and through openings in upperspring seats 188 and 190, respectively. The outwardly extending ends ofthe rod members 180 and 182 are threaded, and nuts 192 and 194 aredisposed thereon and advanced to the point necessary to urge the upperspring seats 188 and 190 against the springs in order to compress themand provide the proper bias, and thus the desired tension in the chains132 and 134. Elastic and permanent stretch of the hoisting rope isautomatically accommodated, and upward movement of the sheaves islimited when the springs 176 and 178 pipe, to prevent slack in thechains due to buffer and safety stops.

In summary, there has been disclosed a new and improved elevator systemof the traction type which successfully extends chain compensation forthe hoisting ropes to elevator systems which operate at speeds up toabout 700 feet per minute, by reducing chain noise and eliminating chainsway without offsetting economic penalties, either in initial cost orhigher maintenance costs. The compensating chain is firmly guided by asheave which has a groove formed of spaced elastomeric members, withalternate links of the chain extending edgewise into the groove, andwith the intervening links resting flatwise on the outer peripheries ofthe elastomeric members, outside the circumferential groove. Thisarrangement provides the silencing and guiding functions withoutscraping, digging and twisting of the chain links, thus providing a lowcost, long life, low maintenance compensation system.

We claim as our invention:

1. An elevator system, comprising:

an elevator car,

a counterweight,

motive means for said car and counterweight including hoisting ropinginterconnecting said car and counterweight,

a compensating chain having a plurality of interconnected links, saidcompensating chain interconnecting said car and counterweight,

tensioning means for tensioning and guiding said compensating chain,

said tensioning means including a sheave and elastomeric means,

said elastomeric means including first and second axially spaced membersdisposed about the outer periphery of said sheave to define acircumferential groove therein having a predetermined width dimension,

said first and second members of the elastomeric means being shaped andspaced such that alternate links of said compensating chain extendedgewise into the circumferential groove, contacting the spaced opposedsides of the first and second members, and the intervening links of saidcompensating chain rest against the outer peripheries of said first andsecond members.

2, The elevator system of claim 1 wherein the first and second membersof the elastomeric means are independent, each having a substantiallycircular crosssectional configuration.

3. The elevator system of claim 1 wherein the first and second membersof the elastomeric means are independent, tubular members.

4. The elevator system of claim 3 wherein the first and second tubularmembers are dimensioned such that the tensioned compensating chaincompresses a portion of each of the tubular members into a substantiallyelliptical cross-sectional configuration, reducing the width dimensionof the circumferential groove.

5. The elevator system of claim 1 wherein the elastomeric means includesa base portion, with the first and second members of the elastomericmeans being integrally connected to and extending outwardly from saidbase portion.

6. The elevator system of claim 5 wherein the first and second memberseach have a substantially circular cross-sectional configuration.

7. The elevator system of claim 6 wherein the first and second membersare tubular.

8. The elevator system of claim 1 wherein the tensioning means includessupport means pivotally mounted at a point located below the travelpaths of the elevator car and counterweight, with the sheave beingrotatably mounted on said support means, and

port means permits limited pivotal movement thereof, preventing movementwhich attempts to raise the sheave beyond a predetermined point.

1. An elevator system, comprising: an elevator car, a counterweight,motive means for said car and counterweight including hoisting ropinginterconnecting said car and counterweight, a compensating chain havinga plurality of interconnected links, said compensating chaininterconnecting said car and counterweight, tensioning means fortensioning and guiding said compensating chain, said tensioning meansincluding a sheave and elastomeric means, said elastomeric meansincluding first and second axially spaced members disposed about theouter periphery of said sheave to define a circumferential groovetherein having a predetermined width dimension, said first and secondmembers of the elastomeric means being shaped and spaced such thatalternate links of said compensating chain extend edgewise into thecircumferential groove, contacting the spaced opposed sides of the firstand second members, and the intervening links of said compensating chainrest against the outer peripheries of said first and second members. 2.The elevator system of claim 1 wherein the first and second members ofthe elastomeric means are independent, each having a substantiallycircular cross-sectional configuration.
 3. The elevator system of claim1 wherein the first and second members of the elastomeric means areindependent, tubular members.
 4. The elevator system of claim 3 whereinthe first and second tubular members are dimensioned such that thetensioned compensating chain compresses a portion of each of the tubularmembers into a substantially elliptical cross-sectional configuration,reducing the width dimension of the circumferential groove.
 5. Theelevator system of claim 1 wherein the elastomeric means includes a baseportion, with the first and second members of the elastomeric meansbeing integrally connected to and extending outwardly from said baseportion.
 6. The elevator system of claim 5 wherein the first and secondmembers each have a substantially circular cross-sectionalconfiguration.
 7. The elevator system of claim 6 wherein the first andsecond members are tubular.
 8. The elevator system of claim 1 whereinthe tensioning means includes support means pivotally mounted at a pointlocated below the travel paths of the elevator car and counterweight,with the sheave being rotatably mounted on said support means, and meansbiasing said support means to tension the compensating chain.
 9. Theelevator system of claim 8 whErein the pivotal movement of the supportmeans is in a substantially vertical plane, and wherein the meansbiasing the support means permits limited pivotal movement thereof,preventing movement which attempts to raise the sheave beyond apredetermined point.